


Playing Our Song

by equilateral_asshat



Category: Gravity Falls
Genre: F/M, pinecest - Freeform, pinescest - Freeform
Language: English
Status: Completed
Published: 2018-12-16
Updated: 2018-12-16
Packaged: 2019-09-20 07:29:24
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 4
Words: 14,650
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/17018370
Author URL: https://archiveofourown.org/users/equilateral_asshat/pseuds/equilateral_asshat





	1. Chapter 1

Growing up twins had never been difficult on the Pines, Dipper and Mabel. They had always been there for each other, as they grew up. For the longest time that he could remember Dipper never felt out of place in the world as long as he had Mabel beside him. She could always get him to smile or laugh somehow, and it always made him happy to his very core when he managed to cheer her out of a funk. They always tackled the majority of their problems together. One summer, when they were twelve, they even saved the world together, along with the help of a healthy smattering of friends, but that never stopped them from reflecting back on that time and using it to remind one another that they had done something huge and magnificent as a team. An “Epic Sibling-duo!” Mabel had proclaimed.

However, eventually Dipper caught himself facing a problem that even his sister couldn’t help him with: the throes and nightmare that is puberty. It had started to rear its ugly head during their first summer in Gravity Falls, but he never anticipated how out of hand it would get. Especially the part about noticing girls, and how pretty all their qualities could be, all the sudden. Especially the girl he’d grown up with all his life. His best friend. His sister.

All too often he had to blink and shake thoughts out of his head, _She’s your sister, stop staring!_ he’d mentally chide himself whenever he caught his eyes lingering for too long. Staring at the way her legs seemed to tone out, how her hips and posterior had rounded out over a few months or how her chest suddenly seemed to have sprang up overnight once upon a time. The real clincher that made his growing, taboo feelings spring to the surface was when she’d finally had her braces removed. The perfect, pearly whites that sat in her smile made his stomach flutter and his heart throb, and finally he figured out that he wasn’t just attracted to his sister, but he was very much in love with her.

Luckily, puberty had been nearly as kind to him as it had to Mabel, first in the form of finally gaining an inch or two on her in the height game. “No fair! You’ve been cheating with that crystal thingy again!” she’d teased, when she finally realized how tall he’d gotten. Then there was the fact that his habit of getting into trouble, then sprinting full tilt from danger, had given him some musculature. _Goodbye, noodle-arms!_ The icing on the cake, though, was when he finally started to grow a beard and, to his own personal delight, a smidgen of a treasure trail. The pool party he and Mabel had attended after it grew in had been a nightmare, though, when she saw it and poked his belly button. “OHMIGOSH, body hair?! Dippin'dots, are you finally becoming a man?!” she’d taunted, wiggling her finger ticklishly at the very top point of the fuzzy path. He was eternally grateful, every time he recalled that memory, for the icy water of the pool that he had immediately shoved her into, but then also dove in to shock his system. _We don’t need any blood migrating south right now, seriously._

Unfortunately, as a teenager he was dealing with that sort of thing happening at almost every turn, at the slightest provocation. Cuddled up on the couch together watching movies like they always had meant he had to sit awkwardly, just so he could avoid further awkwardness. Often he would be waiting for his turn in the shower and when she’d march out, brown tresses soaking and flat against her skin, wrapped in nothing but a towel that only just barely covered her chest and backside. She would march down the hallway after a cheerful “All yours, broseph!”, humming happily while her hips swayed to whatever music was playing in her head. The worst was when he would offer to help her on math or science homework, because more often than not he’d get a hug (a wonderful, tight, squeezy hug that left her breasts pressing into his chest or shoulder) followed by a quick smooch on the cheek. His skin would tingle where her lips had pressed, and it seemed that nature was merciful enough to make sure his blood rushing elsewhere would always prevent a blush.

Late at night, back in his own room, these thoughts would all spiral into his mind in a furious hurricane of perversion. Sometimes he could think unsexy thoughts and the problem would go away. Other nights he had to take matters into his own hands. Or hand, singular. He wouldn’t consciously register what was happening until his brain would begin changing the scenarios that played in the XXX theater of his imagination. Sometimes her towel, after the shower, would be even shorter so he could see the delicate cleft of her rump, or so sheer her nipples seemed to poke through the fabric. Sometimes she’d drop it just for him. Or the homework-help kisses wouldn’t be on the cheek, and they’d be much longer than innocent little pecks. He would bite his lower lip to avoid letting the moans caught in his throat escape, lest his sister’s room across the hall be able to pick up on the occasional mutter of “Oh god, Mabes,” as he would finally hit the breaking point and coat his abdomen with his own spunk.

This ritual was always followed by an indeterminate amount of guilt as he used a wad of tissues to clean himself off. He would then sit at his computer desk, using the internet (in incognito mode, of course! Paranoia kept secrets safe after all) to try and figure out why his brain was wired this way. _Maybe there’s a way to fix what’s wrong with my head_ , he’d hope, clicking through the same few articles over and over again. None of them ever seemed to suggest there was any chemical imbalance causing his issues, just that it was simply hormones causing him to fixate on the closest, most attractive prospective mate. It didn’t matter that his brain knew he couldn’t have her in that way, because his body and its impulses didn’t. _Still doesn’t explain why I can’t convince myself that I’m not in love with my own sister. Or maybe it’s because I was never good at lying to anybody, especially myself_.

Finally, in his junior year of high school, Dipper had struck what he thought to be the “Normalcy” jackpot; the attention of girls his own age. It was an immediate relief when it happened the first time, because it gave him somebody other than his sister to crush on. _Finally, something about Dipper Pines is NORMAL!_ he’d thought on the first date of several he would end up on over the next year or so. There were never any serious relationships, and thus no serious break ups, but every time things between him and a girl would run sour, immediately Mabel was there to comfort him. One time he hadn’t even told anybody, but Mabel picked up on the expression he wore, and his slouchy posture immediately, and had initiated “Twin Time hangouts” before it had even been a full day since that breakup. It was almost like she anticipated it, always seeming ready for such an occurrence.

At one point in time, he’d not really thought twice about this sort of thing, but as time went on he began to notice past clues he’d missed. Sometimes out of the corner of his eye, he’d notice Mabel scowling a bit at one of his girlfriends. Or frowning when she saw their hands interlocked while just watching TV. Whenever he didn’t have a girlfriend around she was bubbly, peppy and overall Mabel. If he had a girl around she acted as though she was being challenged, but too nervous to do anything about it. _I’m probably just overthinking this,_ he would tell himself _,_ _she’s just worried about us growing apart. It’s not like I don’t worry about that, too…_

Truth be told, he always felt their bond was threatened by any of the guys Mabel openly crushed on. At first he tried to quiet those feelings away, trying to convince himself he was just being overprotective of his twin sister. It also got worse whenever one of them showed an interest back. He made an open habit of telling most of the guys that came around to see her that if they stepped out of line, they would have to deal with Dipper. He wasn’t the strongest guy around, but fire in his eyes as he said it made most of them think twice. Anytime Mabel caught onto this sort of thing, she’d argue with him about being a weirdo, and he’d just keep insisting he just wanted the best for her. _Never mind that I wish “the best” could be me…_ he would admit to himself as he lay in his bed sometimes. Those thoughts always got shunted to the back of his mind and locked away for as long as he could muster. _Nobody should have these sorts of thoughts or feelings about their sibling… ugh, I’m a freak._

———  
———

The latter half of their senior year, Dipper got the biggest shock to his system yet during an otherwise normal lunch period. Normally, Dipper sat alone unless Mabel was having one of her days where she’d come sit with him because her friends were all busy catching up on schoolwork, and today was no different, munching absentmindedly at an apple as he read his newest mystery novel from the library. He almost hadn’t noticed it when she sat down across from him. When she cleared her throat, without glancing up he responded with a “Oh, hey sis.”

“Oh please, don’t confuse me for her,” a voice he knew, but wasn’t used to communicating with replied. His eyelids forced a few blinks, and then he placed a thin leather strip between the pages as he closed his book, and then looked up at the source; Rebecca Shmitt. “Seriously, there’s nobody I’d like to be less confused for than your sister, of all people.”

Of all the girls in their high school, Rebecca was widely regarded as one of the prettiest. She was tall, she had more developed and shapely curves than your standard high-schooler, and everything on her face looked as though it had been sculpted from marble. Her jawline was curved and sharp all at once, her eyes were the most intense, striking shade of blue that seemed to chill the air. Her raven black, shoulder length hair hung down in loose curls that could have been either natural, or professionally permed to appear natural. When it caught the light, the shines in her locks seemed to pick up on the blue in her eyes. And here she sat, smiling at him.

He gulped, then did a quick double check around the cafeteria as if scanning for a television camera crew ready to announce he was being punked. He then glanced back at Rebecca, who gave him a small wave with her fingers. Sweat began to bead on his forehead “H-hi, Rebecca. To what do I owe, uh… what is this?” he asked, chewing the inside of his cheek as his hands fiddled with the apple he had half-eaten, staring at the spot directly between her eyes to avoid looking like he was deliberately avoiding eye contact.

“Dipper, I just noticed that you seemed lonely, sitting here, nose buried in a book with nobody to talk to,” she purred. Her lips were curled into an innocent smile as she twirled a lone fingertip on the tabletop. Dipper was torn between courses of action here; one of the most popular girls in his class was talking to him, and she had never previously spoken more than three syllables to him in a row. His natural feeling was to bolt like a spooked deer, but she appeared nonthreatening and nobody was really paying them any mind.

Looking around again, he noticed Mabel sitting and laughing with her friends, engrossed in whatever conversation they were having about boys or something. So, resigned to the concept that maybe, just MAYBE Rebecca was being sincere, he should hear her out. “Well, uh, thanks I guess? I wasn’t even sure you realized I existed, let alone know what my name is,” he said, brushing his hand against the back of his neck.

“Oh, I’m sorry to have given that impression. It’s just that somebody as ruggedly handsome as yourself-” she started, and his brain immediately flew into a different kind of panic, “-rarely manages to escape my radar for so long. You’ve always had your face in a book or you’re busy with a project, or something. I certainly find myself a bit sad we hadn’t had a chance to speak before now.”

 _Okay, Dipper, this is weird. The hottest girl in your class is hitting on you. Openly, in public. This seems weird but hey, we can see where it goes we guess?_ He cleared his throat a bit before he spoke, to make sure his voice wouldn’t do that horrible thing where it cracked and squeaked when he was nervous. _When would he finally outgrow THAT?_ “Yeah, a shame, huh? If you really want to get to know me better I guess we could go out some, maybe go to prom together?” _Smooth, Dipper, for once in your life._

“Oh I would adore that!” she said, those blue eyes glittering happily. “Let’s say you pick me up around 7 on Friday, we can go see a movie,” she said as she scribbled her phone number and address on a slip of paper and slid it to him. He just smiled and nodded, tucking it into his book before she stood up and waved that little three-wiggling-fingers wave before sauntering off.

He sat there, dumbfounded, staring at his book with determination, but the words and letters could just as well have been smears of ink that made nonsensical shapes. His brain tried to process the situation that had just happened. Despite that he had just asked her out, his brain was convinced that Rebecca had coerced him into it. And he’d done it, without fail. This had to be some long, elaborate ruse, right? Any moment now there would be streamers and airhorns and some annoying TV host would shout about how Dipper just got pranked. The anticipation of this terrifying event made Dipper jump with fright when the end of period bell rang.

 _Oh my god, I just asked out REBECCA SHMITT. And she said YES. She wanted me to ask so she could say yes!_ His brain kept replaying those thoughts on a loop as he navigated to his locker as though on autopilot. He screamed aloud when Mabel slammed her hand onto her locker next to his, the sudden sound jolting him out of his confused looping thoughts.

“Hey, broheim! Sorry I couldn’t sit with you at lunch, the girls and I had some crazy stuff to talk about but, nah you wouldn’t wanna hear all that girly crud,” she said, waving the subject off as though she’d piqued his curiosity. When she realized he seemed lost in his own head, she poked one of the dots on his forehead making up his birthmark, shaped like the constellation he was nicknamed for, and it seemed to bring him out of his daze.

“She said yes,” he sputtered out loud, one side of his mouth curling up in a little half smile. Mabel tilted her head like a confused puppy.

“What’s that? Who said yes, to what?” she asked, an eyebrow perked. Dipper laughed out loud as he hugged Mabel tight, nearly lifting her off the ground before he dove halfway into his locker and rummaged for his books for the next few classes.

“Rebecca Shmitt! I asked her out, and she said yes!” he proclaimed before he closed his locker and hurried off to his next class. Had he paid attention, he would have seen the look of utter confusion and disgust on Mabel’s face, as well as heard her when she began muttering.

“No bro-bro of mine is gonna get the claws of that harpy sank into him…”

———  
———

“Dipper, I’m telling you, Becky is-” she had started to protest, but he held up a finger to interject.

“Rebecca. She doesn’t like being called ‘Becky’, and what about her?” he fired back. They’d been arguing on their drive home, and his fingers were gripping the steering wheel of their co-owned van a little harder than was absolutely necessary, causing the fake-leather material to creak.

“She’s a no-good mean poopyhead, is what she is!” an exasperated Mabel said in counter to his statement, arms held up in emphasis. Dipper fought his hardest to keep his scowl going in the face of Mabel’s refusal to swear, because it usually made him chuckle. “She’s a known heart breaker, Dipp, and no good can come of her doing this.”

“Why are you suddenly so interested in my love life when you keep telling me to stay out of yours? If I can let you find your way through relationships, why must you try to sabotage one of mine?” he asked, the question hanging in the air nervously. Mabel squirmed in her seat, arms crossing over her knees as she yanked them up to her chest.

“Bro-bro, I’m not trying to sabotage your love life. I’m saying that from what I’ve seen, Becky is usually up to no good when she takes a random interest in somebody.” Dipper frowned thoughtfully and hung his head, one hand pushing up over his forehead, covering his birthmark as he mulled it over.

“While I appreciate the concern, Mabes, I’d really like to see how this goes, okay? Rebecca is pretty, she’s well liked. I could actually have friends before high school is over! Ever since that weird summer that first time we stayed with Grunkle Stan, I’ve had a hard time talking to anybody but you when we’re home or at school.” He hadn’t meant for the last part to sound as sad as it had, but he had trouble not letting his voice waver dangerously low.

“You have friends! What about those guys in the engineering club?” she said, shrugging. He just shook his head.

“Mabel, we really just bounce ideas around in there. I don’t associate with them outside of the club because we have no other shared interests. It would be nice just to feel like I belong somewhere,” he admitted with a huff.

“Hey, you have a twin sitting in this van arguing with you about this right now, you saying we don’t belong together?” she blurted out, followed by a stammered “A-as friends?” He glanced at her out of the corner of his eye. _Is she blushing? Nah, has to be a trick of the light._

“Mabel, I really appreciate you looking out for me, but I need to ask you to let me do something on my own for once.” He punctuated the request by turning the van off as they pulled into their driveway, sitting there in his seat wordlessly as the engine cut out. Mabel huffed again, then just hopped out of the van and slammed the door as hard as she could muster, stomping her way to the house and inside before he even moved from his spot.

“Ugh, Mabes, you’re harder to figure out than the girls who actually show interest in me, and I’ve known you my whole life. What do I need to do to make you happy for me?” His question to the empty air went (graciously, for now) unanswered as he grabbed his things and trudged up to his room. _Schoolwork,_ he could always lose himself in schoolwork.


	2. Chapter 2

Friday couldn’t come soon enough, in Dipper’s opinion. The anticipation of being on a date with Rebecca filled him with glee, despite Mabel’s ongoing protests. She kept mentioning various scenarios where Rebecca had broken the hearts of anybody who slighted her the tiniest bit. How she was only so popular and well liked because of how pretty she was, and most of her friends would badmouth her when she wasn’t around. It was a never ending tide of negativity, so he started to be grateful, if a little bit sad, for the wedge that seemed to be pushing itself between him and his sibling. _At least I don’t have to keep hearing her badmouthing my new girlfriend._

When Friday finally did arrive, Dipper made sure to wear his fanciest (cleanest) button up shirt, and a pair of black slacks that were somewhat boring but, at least, did the job pants were supposed to do. He drove out towards Rebacca’s house while giving himself a fifteen minute leeway, just in case he got lost. Fortunately, her address was easy to find. Unfortunately, the nerve wracking implications of being so early made him feel like he’d seem desperate.

 _Well, Dipper, if we’re being honest with yourself, you kind of ARE desperate! Besides, in the wake of this you haven’t had any of those… those WRONG thoughts about Mabel._ He quickly shook his head as that thought surfaced, because shortly behind it were all of those thoughts he just told himself he hadn’t been having, racing to make him remember every unclean thought or taboo emotion that he’d managed to hide from recently. For once, he was glad that the stress of his current situation was making it hard to think as he pulled in front of Rebecca’s house. The stress of this first date made it hard for him to form a coherent thought for more than half a second, which made it nearly impossible for the bad thoughts to stick around if they managed to hit.

He timed his walk perfectly, arriving at her door at 6:59:57, giving him three seconds to steel his nerves and knock at 7:00 on the dot. A tall, statuesque man with rigid features and a heavy brow opened the door and stared down at Dipper. His dark eyes seemed to pierce Dipper to the core as they stood and watched each other silently for a few seconds. “Uh, excuse me, is Rebecca h-” he started to ask before the man, without breaking the glare, somehow turned and shouted back into the house.

“Honey, your date is here!” A loud, nervous gulp matched the bob of Dipper’s Adam’s apple as the giant turned back to resume staring. His eyes narrowed at Dipper, who was having trouble not shriveling away as he sweat profusely. The man’s eyes then glanced out at the curb, passing over the old van he’d driven here. “Hhmm,” he grunted, as if approving. “Sturdy little number. Looks like you drive it carefully, you bring'er home safe.” He gave Dipper a powerful clap on the shoulder to punctuate the word _safe_ , then turned just as the click of Rebecca’s heels sounded behind him, clearing the doorway to let her step through.

She was wearing a dark grey dress and had on a shade of soft red lipstick. She smiled at Dipper, then turned to the sentinel who had opened the door. She tiptoed up to kiss his cheek gently. “Thank you Daddy for not scaring off another one,” she said before she held out her arm to Dipper. He instinctively hooked his through it and led her towards his van, glancing back towards where her father stood, watching. It wasn’t until Dipper had let her in the van and turned back around that her giant of a father had just nodded at Dipper again and backed away before silently closing the door.

“Does your father EVER blink?” he asked as he piled into the driver’s seat and buckled himself in, chuckling nervously. Rebecca merely waved the question off with a sigh.

“Daddy likes to be intimidating, he doesn’t want his precious princess getting hurt,” she mused, picking at the edge of a fingernail as Dipper drove them towards the theater. They arrived with more than enough time before anything was going to start, giving them plenty of time to loiter at the snack bar after he bought the tickets. And then all of her snacks. Then they went and sat through what Dipper had to conclude was the worst two hours of romantic comedy that had ever been written in the history of known literature, let alone film. But, Rebecca kept laughing and, at one point, had tugged his arm around her shoulders and leaned into him, so maybe it wasn’t SUCH a bad film?

Mercifully, the film ended sooner than he had anticipated, and before long the two were arm in arm, headed for his van again when she suggested they get some quick dinner at a nearby fast food place. While they sat and nibbled their way through the meal, Dipper began to get nervous. The silence between them in that moment was deafening. _Oh man, did I screw up this date somehow? Is prom a no-go? Fuck, fuck, fu-_

“So, Dipper, about Prom?” she asked, his brain flat-lining for all of two seconds. He nodded when she looked up, pretending to have a mouthful of food so he couldn’t speak. “I have to make sure we’re on the same page about that, and here’s what I had planned out,” she said, reaching into her small purse to pull out a tiny  journal, flipping it open, then turning it towards him as she began explaining the checklist. Numbers for a limo place and what kind of limo he had to rent, what time he would pick her up, how long they would be at the dance, and so on. He heard it all, and nodded as she spoke, but his brain was too noisy for him to register it at the exact moment.

 _Rebecca makes lists?! She plans this stuff out so it all goes perfect? Man, just when I thought this couldn’t get better!_ he thought, a smile spreading over his face. He was even more excited, now, because not only was she still going to prom with him, but she had a plan.

———  
———

 _Stupid stank-brained Dipper. He won’t even listen to me! And he hasn’t even tried to apologize since our last argument about this…_ Mabel was sulking on her bed, wearing one of her oversized sweaters as she chewed on a few overly-sweet gummi koalas. Whenever she was sad, she’d retreat to her room and feed her crushing addiction to sugar. She wasn’t sure how her teeth or pancreas survived her dietary habits, but she figured she had built up an immunity.

Deep down, Mabel was really happy for Dipper. She was always happy for him when he found a girlfriend. She’d had so many boyfriends over the years, and had noticed that Dipper was secretly jealous of them. She knew how he felt, because she was also worried about one of them getting too caught up in their own love life to still be the dynamic duo everyone had known them to always be. _Oh, don’t fool yourself, Mabel-Grabel. We all know it isn’t just the fear of losing the sibling bond._

Years back when they had simultaneously been hit with puberty, things had gotten awkward between them. Dippers initial growth spurt had threatened her alpha-twin status, like seriously who was he to go and get taller than her?! She was the older twin, though, and she still clung rabidly to that. Then, after getting taller, he’d packed on muscles. And then he’d actually started to grow body hair. And oh man, that treasure trail she’d noticed him debuting at the pool party?! She’d almost lost her cool and touched it, and if she had touched it, people would have known. _No one must ever know, ugh._

 _Hey Mabel, why haven’t you had a boyfriend for the last six months? Usually you’re after some great guy. Well, you see, it’s because I have been an absolute sick-in-the-head-doofus and fallen for my brother. Ugh._ Admitting it to herself, even silently in her own buzzing, colorful mind made her blush furiously. It wasn’t her fault he’d gotten so… rugged! And that little beard he had coming in, oh man if that got any fuller before they graduated she might lose control and do something regrettable.

 _And no, it’s not enough that you had to go and get handsome, Dippingsauce, you ALSO had to be a total sweetheart and worry about my own happiness at every turn. You ignore your own homework to help me try to figure out mine, you tolerate my surprise twin-dance-parties, you always know just how to cheer me up, and you even did run off a few boyfriends I only got to see you run them off. Like you were chasing off somebody too close to your woman._ A wistful sigh escaped her. Nope, sitting up here in this bedroom, eating these delicious, unfortunate gummy marsupials one at a time to forget her woes wasn’t going to work. So, she made herself stand up, and march down the stairs to the living room.

“Mom?” she called out, getting no response. Probably working late again, she thought as she made her way to the kitchen and indeed, there was a note hung on the fridge to confirm those suspicions. Mom usually worked late shifts at the hospital, and their Dad had gotten called off to a last minute conference a few towns over. The twins loved their parents, and while they weren’t exactly BAD parents, as the years had gone by Dipper and Mabel had practically started raising themselves. Which wasn’t so bad, in her mind, because it meant they had bonded even more. _Then again maybe if the folks had stuck around more I wouldn’t have had time to start feeling this way over my bro-bro._

After digging out a bowl, some sugary, marshmallow flooded cereal and the chocolate milk, she managed to lug everything to the living room and spread it out across the coffee table as she flipped on the TV. After a few channel switches, she landed on a garishly 80’s movie marathon channel and settled in with a bowl of cereal so laden with sugar anybody else would develop diabetes in one bite.

Once she’d had her fill of sugary, crunchy, chocolaty things, she packed everything back to the kitchen and returned to the couch. She eyeballed the clock on the wall and sighed. Dipper still had at least an hour on his date with Becky. Saying the name out loud made her want to gag, and thinking it still left a nasty, sour bile taste in the back of her throat. Ugh. She had seen that girl ruin the lives of men who hadn’t done everything exactly the way she wanted them to. If one of her boyfriends had ever stepped out of line or made an honest mistake he lost any semblance of respect that he had among classmates. And, much to Mabel’s dismay, the next sap she’d lined up at the social guillotine was her brother.

 _Poor Dipper, I wish you’d just let me explain instead of shutting me out,_ she thought with a mope. _Maybe, he’ll break up with her tonight, yeah. And then he’ll come home, tell me how I was right all along and “Oh Mabel, how can I ever repay you?” and I can say “A kiss would be a nice start…”_ Mabel’s head began to go fuzzy as her train of thought drifted. While her mind drifted, so did one of her hands, down over her sweater clad stomach, then up beneath the fuzzy shirt and back down into the waistband of her shorts and lacy underthings. She gasped, the touch of her fingers translating to Dipper’s strong, rough digits playing over her button in her own fantasy. Every touch was like shocking herself with a tiny taser, sending jolts through her joints and system. She squirmed, legs clamping together, free hand balling into a fist against a throw pillow as she panted.

Of course, she was just teasing herself for now. No, the real party started as she plunged her hand a bit deeper and one of her fingers hooked up and in, hitting her slick, sensitive walls and making her squeak. _A-and then, he’d bite me on the neck just ever so lovingly, growling before he lets another finger join the first_ -she mimed the action, strictly for authenticity of course, her hips shuddering as she felt a coil build up in her torso, tightening swiftly- _and then right as he kisses me on the lips he’ll tell me how he’s ready to throw caution to the wind and let our forbidden love flourish before he sweeps me up in his hunky, muscly arms, takes me to the bed and-_ “ffffuuuck, Dipp!” she moaned aloud. And at the worst possible moment, too, because she heard a key click in the lock. _He’s home?! **NOW?!** OHNOHNOHNO._

Her hand hastily yanked itself free, fingers still covered with a wet sheen, and before Dipper could fully open the door she ran up the stairs and threw herself through her bedroom door, shutting it a bit harder than she’d meant too. Downstairs, she heard him scream softly and groan.

“What did I even do this time?!” she heard him say, and she sighed as she flopped onto her bed with a whimper. _Nothing, it’s what you can’t, won’t? Either or I guess. It’s what we shouldn’t do…_ Unwilling to finish what she’d started on the couch, she buried herself in her bedding and fought tears as best she could as she drifted to sleep.


	3. Chapter 3

When Dipper got back home after his date, his head was still dizzy with the thoughts of Prom and how Rebecca wanted everything done, cataloging every tidbit of info he could retain. He had managed to compile a decent list of information on the drive back to her place, making an effort to still pay attention so he could remember it all for later. Only when he parked in front of her house and exited the van to open her door did he have a silent moment to quickly shove everything into the proper mental folders.

“So I guess I’ll see you at school on Monday,” he said as she nodded with a brief, polite smile. Rebecca reached up, cupping his cheek, and before he could think to lean in for what he believed to be an ensuing kiss, she gave him a pat on the cheek.

“Of course, hon. Of course. Thank you very much for the date!” she said, gently shifting past him to saunter up to the house. _Okay I didn’t get a kiss, but watching her walk away is fantastic_ , he mused internally as he made no effort to avoid staring at her butt. Eventually, though, he had to wrench his eyes from that round rump so he could get in the van and drive. Also, he needed to do that-the not still staring at the ass thing-so he could focus on mentally organizing the details she had laid out of their Prom plan.

As he turned the key in the lock, he could swear he heard Mabel’s voice, and before he even had the door open she was stomping off to her room, slamming the door. “What did I even do this time?!” he groused, raising his hands in exasperation. He decided that he shouldn’t dwell on it. He marched himself up to his own bedroom, across the hall from Mabel’s, and thought better than to slam his own door, closing and latching it softly. “I just wish we could get along again…” he sighed, staring at his door as though straining to develop X-ray vision to see what Mabel was doing.

After a few fruitless seconds, he huffed a defeated sigh and planted himself on the edge of his bed. Peeling out of his shoes, shirt and pants took forever, and he laid back in bed, staring at the ceiling as his brain buzzed with a dozen different topics at once. Prom, Rebecca, Rebecca’s sweet ass, that horrible movie he had to endure to see said sweet ass, Mabel hiding from him and avoiding him at all costs, that sweet ass again. And around again, and again until he fell asleep, unremarkable dreams overtaking his night.

———  
———

By Monday after school, it had become apparent to both of the twins that the current “not talking to each other while living in the same house” thing wasn’t working. Neither was certain which one would be bothered to speak up first, they just seemed to both sit down in front of Ducktective reruns and start talking again. About four episodes in, Mabel cleared her throat.

“I’m real sorry how I’ve been acting since you started seeing Rebecca, bro-bro,” she said quietly, fiddling with a lock of hair while she said it. When she looked up at Dipper, she caught a smile on his face, his expression just as apologetic as she hoped hers was.

“No, don’t worry about it. I’m pretty sure if it was you dating somebody I never saw reason to trust, I’d be just as weird about it as you’ve been. This whole twin thing?” he said, motioning between them with an open hand, “this makes us worry about the other, and we have a tendency to take things to heart way too fast. Awkward sibling hug?”

“Awkward sibling hug,” she agreed, scooting over to snatch him up in a quick embrace. The hug was only a second or two long, without any major lingering or body-parts smooshing or any of that, but they both seemed to inherently know when it was time to break the hug, each of them patting the other on the back.

“Pat-pat,” they spoke in monotone together, then simultaneously bursting out into a fit of giggles. From there, it seemed, things got easier. They finally returned to their study-buddy habits, watching horrible TV shows together, and overall were back to being siblings. It was as if they had never fought, but then again they had always had trouble staying angry with one another. Eventually one or both of them cracked and, like they just had, amends were made so they could resume acting like twins and friends.

A few days went by like this, perfectly, but Dipper noticed that despite the fact that they’d agreed to let bygones be bygones, Mabel avoided him if Rebecca was anywhere nearby. If they were at their lockers and laughing at a shared joke, Mabel would suddenly look past him, expression going from mirth to dread before she would spin around with a “Gottagettoclass,” and then Rebecca’s voice would pipe up behind him.

“I don’t know why she seems uneasy around you,” he remarked once while he and Rebecca walked down the hallway, all of her books stacked in his arms on top of his own. “I wish she would at least warm up to you and actually hang out a bit, I’m sure you two would get along eventually.”

“Dipper, dear, as far as I’m concerned whether or not that happens is no matter to worry your head over,” she said dismissively. She always acted so indifferent whenever he brought up Mabel. At first it just seemed like maybe it was a teenage girl thing about them not being in the same clique, but sometimes it started to feel angrier, as though somehow Mabel had wronged his new girlfriend in some way, but he could never pick it out and he worried that digging at the subject would lead to relationship drama. He had just managed to sort out drama with his sister, he didn’t need it from a source that he could actually and openly show romantic tendencies toward. “Now then, Prom is in a week. We really ought to refresh your wardrobe and whatnot.”

Dipper paused, giving her a confused look, then staring down at his own clothing; he was clad in his typical ensemble of a loose flannel shirt over a plain tee, comfortable jeans and a set of hiking boots. He twisted this way and that to see if he was covered in stains, but no, it was all clean, all slightly faded, maybe a tad too hipster for his own tastes but damn if it wasn’t the most comfortable way to dress. “What, uh, what’s wrong with my wardrobe and my whatnots?”

“Oh, hon,” she said as though she were talking down to a small child. “You look like a fledgling lumberjack that has yet to hit… whatever lumberjacks have as a puberty equivalent. And you could really stand to shave that thing on your chin,” she noted, a hint of a sneer on her face. He rubbed at his chin with a thoughtful frown.

“It’s not that bad of a beard, even Mabel said she thought it was kind of cute and-” he started, but Rebecca snapped her fingers angrily at the mention of Mabel.

“It doesn’t even meet the standards to qualify as a beard yet, and you really shouldn’t consider what your sister has to say over your girlfriend’s opinion, on looks. I mean, it’s not like you’re dating her,” she retorted. Dipper sighed, realizing that despite his own objections (seriously, it had taken two months to grow in as nicely as it had and now he had to shave it off?!), Rebecca had a point. He had left it to grow as long as he had because of a compliment Mabel once paid him. Most of his fashion choices and self image ideas were actually because she would comment on how she liked the way it made him look. But, he wasn’t-and couldn’t be, really, because the big “I-word” was morally wrong-dating Mabel.

“Yeah, yeah, I guess that’s fair. So did you want to help me go shopping after I rent my tux or…?” he offered, and she scoffed.

“Rent?! No no no, I can’t go to prom with you in a tuxedo that several other teenage boys have been in like some sort of secondhand monkeysuit. I’ll take you to a store and we’ll get you fitted proper,” she said with a matter-of-fact atttitude as they arrived at the doorway of her next class and took her books from him. “We’ll make it a date.”

He knew there was no arguing this. He just nodded with a sound of approval. It seemed lately that Rebecca had been making decisions for him, and it dug at him just enough to cause him to start wondering if just maybe Mabel had been right. But then he decided that if normal relationships took work, then by god he would try. “Yeah, okay.”

———  
———

Saturday’s “date” seemed more like a chore than anything resembling going out to have fun with your significant other, to Dipper. First he endured an hour or two of being made to change into nearly a different dozen tuxeos, with Rebecca dismissing them for a host of reasons. Too bland, wrong color, “Ew, green is awful on you,” and so on until she had settled on a classic style with a red vest and bow tie. Almost exactly like the one he had seen at the rental place a few days earlier. For a third of the price. Ah well, he had better just roll with it for now. There was a plan for this upcoming dance, and he took checklists seriously. If she had this in her plan, so be it.

After dropping a substantial wad of his own money on the suit, next he was subjected to a fashion-show like montage of changing clothes in a few snooty name brand locations. The one that threw him off the most was the store where it was so dark you could barely see, and in place of mannequins they had shirtless male models. “You would think if they wanted you to buy these shirts they’d make these guys put some on,” he mused out loud, trying to remember the joke to tell Mabel later. It was the kind she’d appreciate. Rebecca, meanwhile, just snapped her fingers in that familiar be quiet gesture that made the skin on his scalp tingle in an angry way. _Remember, Dipper, normal girlfriend, normal life, don’t fuck this up._

Once again he dropped more money than seemed logical, on a bunch of name brand clothing he’d never wear if he could have helped it, but oh well. _Normal, normal, normal. This is what I want right?_ The more he repeated it to himself, the less he felt it in the back of his mind. But he had to do this, not just for his own sake, but before he also did something that would ruin not only his life, but his sister’s as well. If he could be normal, there was no longer a risk of those taboo feelings welling back to the surface. This was as much for his sister’s standing as well as his own.

———  
———

Upon arriving back home with several bags of clothing he never really intended to wear, Mabel met Dipper at the foot of the stairs, confusion evident on her face. “So uh, Dipster, you secretly taking up a career as a male model?” she teased, eyeballing all of the brand names. He sighed and shook his head.

“No, Rebecca thought I could use some new clothes, so she took me out and found some stuff for me to buy,” he begrudgingly admitted. Mabel’s half smile quickly turned downwards, her brow furrowing with displeasure. “What? I wear the same thing almost everyday, maybe I could use an update.”

“Dipper, this girl is trying to change you to fit her own personal image,” she objected, and despite her grumpy expression her voice was full of nervous sincerity. Clearly she had been thinking of this for awhile. That only made what he said next more difficult.

“Maybe… maybe I need to have some stuff about me changed to be more acceptable,” he grumbled, gulping hard. “I don’t feel like I really belong anywhere but with you, Mabel, but eventually we have to go different ways. Find our own lives, yanno? And I don’t think I can do that unless I spend a little bit of time remaking myself. I love you, Mabes, and I’ll always be your brother, but I need to learn how to talk to, and relate to, people other than just you.”

“W, what?!” she said, and he could practically hear the tears in her voice. “Are you saying you don’t like us being friends?! We were the mystery twins, Dipper! We’ve always been a team!” Yeah, definitely crying, he heard the sniffling a few times between words in that last sentence.

“Mabel, you’re the best friend I have, that I have EVER had, but you-” he explained, grunting in frustration as he balled his fists up aginst his forehead, tapping them there repeatedly as though trying to jar thoughts loose while the bags of clothing shook in his grasp. “You can’t always be my ONLY friend. Like I said, one day we won’t live together anymore, and I can’t just be by myself forever! You’re going to eventually find a guy, start a family, you’ve always wanted that right? If I don’t learn how to have other friends, I’ll always be hanging around. How can you find the right guy if your brother is glued to your side?”

Upon getting these feelings off of his chest, he stared at Mabel and realized, through his blurry vision, he was crying harder than her. He dropped all of his bags and sat heavily on the bottom step, unable to keep eye contact. If he didn’t look away, every feeling for her he had, all of that lust and pining for her, would bubble up to the surface and out of his lips when he was like this. Deep breaths, Dipper, deep breaths.

He wasn’t certain how long the silence persisted, with her standing there over him, sniffling occasionally, his own shoulders shaking as he tried to contain the random sob that made a try at hopping up out of his throat. It made him jump when he felt her sit right next to him, then lean over and bury her face against his shoulder, trying to dry her tears there.

“I’m sorry, Dipp. I didn’t realize that, yanno, you never really connected to anybody else. We’ve just always had each other and I try not to think about what it will be like when we don’t,” she said as she hugged her arms loosely around his torso. On instinct, his arm loooped up around her shoulders in a half-hug as he turned his head and planted a quick, loving kiss at the edge of her hairline and forehead. “And I didn’t know that you were so worried about how you make me look or feel. I guess I’m pretty selfish with your feelings, a lot of times.”

“Heh, well sis I grew up with you and that’s the truth, sometimes. But I can be just as bad. I tend to get greedy when it comes to getting your attention. Why do you think I have a tendency to run your boyfriends off?” he asked, giving her a gentle shake. She made a small ‘pbbbtt’ noise with her tongue and giggled a bit.

“I dunno, either you thought I was a sweet innocent maiden in need of a guardian-” she started, to which he scoffed lightly, drawing a pinch to the ribs from her, “-or that you might have had some sort of weirdo crush on me, but pfffft you’re too smart for that sort of thing.” He went red in a flash, and he managed to mask the cough of surprise by sniffling again, pretending to clear his throat afterwards.

“Heh, sure, too smart. Hey, Mabes?” She tilted up to look at him, her eyes puffy but tearless as she curled up the corner of her mouth. “I’m sorry I keep so much of what scares me hidden from you. Ever since we got you out of that prison bubble when we were twelve, I’ve dreaded seeing you get hurt more than anything else. I can’t lose you again, and I get a little possessive over that.”

“All is forgiven, Sir Dippington,” she said as she gave him a squeeze, then unraveled herself from their awkward embrace to smooch at his cheek. Is it my imagination or is she lingering longer than normal? “Just, try to be more open about this stuff in the future, 'kay?”

“Well, I can’t tell you everything. Remember how much it bugged you the last time you went through my internet history?” he joked, and she pretended to gag.

“Oh gods, don’t even-no, nuh uh, let’s just leave that as our most awkward of sibling moments,” she said, practically begging, but then they both ended up laughing as he stood, re-gathered his bags, and gently bumped her with his hips before they ascended the stairs to retreat to their bedrooms.

_I wonder if all twins go through this stuff._

———  
———

Mabel flopped on her bed, still choking down the occasional stray sob from the sudden cry-session the twins had just joined each other in. She popped a green gummy koala into her mouth and chewed thoughtfully, not really tasting the rush of sugar.

 _Man, Mabel-Grabel, how could you not realize how greedy you act with him?_ Her eyes screwed shut as she huffed at herself. _That poor dumb dork, he’s so worried about me, in all of this he’s ultimately worried about how it makes ME look._

She scowled thoughtfully, chomping the head off of another jellied marsupial _. I could have swore I voiced to him before that I was just worried about what Becky’ll do to him after one slip up. And she made him SHAVE?! Ugh, stupid Becky, fuzzy Dipp is hottest Dipp._ As that thought flashed through her mind, she slapped herself on the forehead with the heel of her palm, repeatedly.

 _Get out of there you sinful, sinful thoughts!_ she chastised herself. Of course, deep down she knew that she’d just fallen harder for her own brother, upon hearing about how this whole thing with Rebecca was more about trying to make his sister’s future more secure. _Of course, that’s what he keeps saying. Pretty sure he was redder than normal flustered Dipster when I let that kiss go a little too long. Am I just imagining…_? A defeated sigh left her as she finished off the headless koala, grumbling as she rolled onto her stomach, burying her face in a pillow.

_I wonder if all twins go through this stuff._


	4. Chapter 4

Since their last-what, would people call that a fight? No, more like a mutual cry-it-out session, Dipper thought inwardly, things between himself and Mabel had improved. His sister even seemed less afraid of his girlfriend, though anytime they saw each other at his locker both girls would just say “hi” or something equally blunt and short on syllables. But, progress was progress, no matter how small, and he was going to take it over the two avoiding one another. Still, it stung a bit that while Mabel seemed to be making an effort to warm up to Rebecca, his girlfriend still seemed hesitant, and sometimes dismissive of his sister’s attempt to be social with her. That wasn’t the worst of it, though.

As the days went by, he noticed that around Rebecca, he never felt quite like himself. Sure, people were being nicer (or maybe just bothering to pay him any notice, he wasn’t convinced which one it was yet), complimenting his new outfits and talking to him, but it was only when she was around. And he also hated to admit it but the longer this relationship went on, the more and more he felt like she was refusing to let him be himself. If he said something when she hadn’t been talking directly to him, she’d do that stupid finger-snapping thing, ugh. But, he wanted this to work. He wanted to be able to make more friends, expand his social circle, right? _Isn’t that what I wanted? Get more friends, be able to get my mind off of those incestuous thoughts?_

Being perfectly honest with himself, he realized that school days had become a trial and he usually looked forward to the drive home with his sister. They would find songs on the radio, sing along or try to out-sing one another, sometimes changing lyrics up to poke fun. One song, though, that got them going into a duet mode (they claimed it was secretly about them) every time it played had started pouring through the speakers, and Mabel took the lead in singing, each of them taking their turn at a verse.

“Heeeey, brother, there’s an endless road to rediscoverrrr!” she belted out, making no effort to hit the right notes or an appropriate volume, making Dipper choke back a laugh as he prepared to sing the next line of “Heeeeey sister, no the water’s sweet but blood is thickerrr!” Then, without missing a beat, they both piped up for the next line.

“Oooooh, if the sky comes falling down, for you, there’s nothing in this world I wouldn’t doooo!” they rang out together, off key, voices cracking as they ended up laughing over the next verse of the song before Dipper bothered to turn the radio down.

“I missed this,” he said quietly, glancing over at his twin sister while they sat at a stop light. She smiled back, her sad grin matching his own. _It’s like looking in a mirror that makes me prettier_ , he mused to himself before he spoke up. “I missed us being, well, US. You know? We haven’t been the best siblings lately and I feel like it’s my fault.”

Mabel shook her head defiantly. “Nah, Dipper, I’ve not been the most supporting and understanding of sisters to your current cause. I keep forgetting that just maaaaybe you need to let somebody around make you feel closer to normal. Rebecca helps with that, I guess, and it’s not right of me to hate on her for it.”

“Heh, yeah, well, I’m hoping something shifts at Prom, tomorrow,” he noted. He could feel the eyes boring into him from across the van so when he pulled into the driveway and killed the ignition, he glanced over to find his sister giving him a concerned stare. “I just, she’s getting a little out of control? Or rather more in control, of everything. Part of me hopes it’s just that she’s nervous about this dance going right, but, I’m worried?”

As Mabel leaned towards him from her seat, he could feel sweat dotting his forehead and slicking his palms, all from the look she was giving him. Her eyebrows were furrowed worriedly over her eyes, which seemed to be flooded with concern. And she kept getting closer, never breaking the gaze she had him in. He swallowed before clearing his throat, and managed to blink away from her stare. “Yeah, that’s probably all,” she finally said as she reached out to poke his nose with a ‘boop!’ and then make her way out of the van and towards the house. When he could finally breathe again, he grabbed his own things and followed after her. He was having trouble getting that look she gave him out of his head; there was more under her eyes than concern for her brother, much more, but he couldn’t place it.

_I have lived with you for all of our lives and you still confuse the hell out of me, Mabes. What is going on in your head?_

“Oh, so, hey, we haven’t been the best at communication, lately,” he said as they sat on the couch. “Who are you going to Prom with?”

“No dates for Lady Mabelton, this year, my good Sir Dippingsauce,” she said before she dramatically balled a fist up and thunked her chest for effect. “This gal’s goin’ stag!”

Dipper couldn’t help but chuckle at that. “I’m not _entirely_ sure they still call it that when a girl does it? And really, you, Mabel Pines, the boy-craziest of girls is going to a school dance WITHOUT a date?”

She shrugged and made a brief raspberry with her tongue. “Eh, boys are kinda poopheads, and the well at school has run a bit dry for date-material on my end of things, yanno?” Dipper just nodded, smirking.

“Heh, if I wasn’t dating Rebecca we could have gone together,” he thought out loud before he could stop himself. Mabel’s head whipped over to stare at him as he cracked open a can of Pitt and drank noisily, staring at the wall. “I mean, yanno, drove there together, just had fun as brother and sister. Do the twins thing.” When he shifted his gaze out of the corner of his eye, he could have sworn she was giving him the same look he’d got from her in the van.

“Hmmm, yeah that would’ve been fun,” she finally relented. “You better save at least one dance for me, though, bro-bro. We’ve gotta make up for lost time. No dance offs for what, two months now?!” He just guffawed at her exasperated voice.

“You’d just win if we had any,” he noted and she nodded.

“Well, doi, I AM the Alpha-twin.” She punctuated her statement with crossed arms, a stern look and a brief nod. Then broke into a fit of laughs, which he joined her in. Maybe this dance would solve all of his problems, right now.

———  
———

The morning of Prom arrived to a pair of siblings hustling to help one another with all the little details. Mabel had Dipper try on his suit once, and then groaned a bit. “For a fashion dweeb your girlfriend took you to a lousy tailor, here,” she said, pulling him out of his jacket and shirt, leaving him in just his pants. He flushed pink, but thankfully Mabel had already sat down at her sewing machine, making furious alterations to his ensemble. Once she was done, she insisted on redressing him which made him blush even more, but she was more worried about getting him slid into his outfit than she was with his face. _Thank you, sweet merciful powers of the multiverse that you have spared me from her looking at my face right now._

When he looked at himself in the mirror, he was astounded. The tuxedo suddenly looked like it had been made just for him. Everything sat on his frame right, with enough room to bend and wiggle without it looking massive on his wiry physique. “Wow, sis, thanks! This is, this is better than I even expected,” he said, and she beamed.

Later, as she sat and busied herself painting her fingernails in gradient shades of pink and purple that sparkled to an almost obscene degree, she had him carefully coiling her hair up into a style that required so many bobby pins to hold in place it seemed ridiculous. But, between the tutorial video he’d pulled up, and his steady fingers, he’d managed to hide almost every single one of the offending little wire clips, and she gave him a quick squeeze around the middle as thanks before she took off to her room to finish getting herself ready.

“So hey, oh handsome brother of mine, tell me how I look?” she asked as she gently descended the stairs. Dipper was dumbfounded, and it took him a moment to process words as he took in the sight.

Every taboo thought that had finally escaped him over the course of his current relationship flooded to the front of his brain, eyes scanning his sister’s outfit hurriedly. First his eyes scanned over her makeup, which was subtle and modest, bringing out the natural, soft beauty she’d had. The only thing on her face that glittered, surprisingly, was the purplish-pink lip gloss, and even then only fleetingly, at the edges.

She’d donned a purple dress that only had one strap, which seemed to be mostly for show. His mind boggled at how she had managed to keep it from slipping off of her chest ( _double sided tape maybe?_ ), and his eyes felt a little blinded by the amount of sequins on this thing. It gripped tightly around her waist, blooming out at the hips in layers of ribbony satin and tulle-netting, the lowest hem dangling somewhere between her knees and ankles. She gave a small twirl, laughing. “Well, are you gonna say something? I didn’t spend a week and a half modifying this for stupefied silence.”

“Y-you, look stunning, Mabes,” he said, eyes still looking over every detail of her outfit. She just chuckled and smiled graciously, ears reddening a bit at the tips. She leaned up on her tiptoes as she walked up to him, his arms crossed behind his back. He began to sweat nervously as her face hovered near his, eyes lazily boring into his own. “Uuuuhhh….”

“So, since you have a limo tonight you won’t need… THESE!” she declared, and before he could respond she had somehow swiped the van’s keys from his pocket and taken off, cackling. He took off a split second later, chasing after her.

“Mabel! You’re my ride to the limo place!”

A quick drive to the aforementioned limo rental business had her dropping him off and taking the van herself, with her still snorting as she giggled about her “attempt” to leave him at home. “Go get'er, tiger!” she teased with an eyebrow waggle before driving off to the dance. Dipper nervously rode in the limo to Rebecca’s house, coming inside and making forced small talk with her parents before she came down the stairs.

Dipper was certain that if they could have, his eyes would have popped clean from the sockets and rolled away. Rebecca was donned in a silky red thing that seemed to hug every curve on her body, a deep V in the neckline showing off perhaps a bit too much cleavage for somebody her age, and a similar slit up just past the knees on one side of the skirt portion. She walked delicately on heels that made her just as tall as he was, held in place by tiny little straps. Her lipstick was a shade of red to match that of the dress, and it reminded him of a poisonous-yet-lovely flower. He stammered for a bit, then cleared his throat.

“Wow, Rebecca, you look amazing!” he managed to spit out, before she just grinned and nodded, her black coils of hair bobbing slightly.

“I do, don’t I?” she said with an exaggerated twirl, before she turned and locked her eyes onto his. “I trust you didn’t forget my corsage?” He hastily pulled the refrigerated flower out, fastening it around her wrist. She admired it for a bit, sighing wistfully. _You better like it, you picked it out, just like EVERYTHING else,_ he groaned in his own head.

“Shall we go to the prom?” she asked, her voice airy as she held out her hand. He gently took it in his own and led her to the limo, before helping her in and then climbing in himself. The ride to the school was silent, with her sitting in her seat, hands delicately folded in her lap. He hated the silence, but he knew that there wasn’t much to speak of at the moment, so he just kept his mind on the dance ahead.

_Finally, a date to the biggest dance of my high school career, and she’s the prettiest girl in the school! Well, not as pretty as Mabel was tonight. BUT she’s my sister and I am NOT comparing the sex appeal of my date to that of my own flesh and blood! We’ve been over this brain, we are NOT having sexy thoughts about our sister! Even if her dress was amazing, and pressed her breasts up and together in that special way and-NO. No I said!  
_

This internal argument carried on for the entire ride, sweat beading along his forehead and dotting the spaces bordered by his birthmark. If Rebecca noticed, she said nothing, and he managed to stifle the thoughts before they arrived. _Okay, time for us to make our entrance…_

———  
———

As soon as they arrived (right on time, as per her instructions for the evening), she drug him to the professional photographer’s stand and they had their picture taken. Then, almost immediately, as the music started, Rebecca turned and handed Dipper her tiny red purse. “Here, hold this for me, I need to go find some people and socialize a bit.”

“Can’t I, uh, come with you?” he had asked, and she just laughed it off with a wave of her hand.

“No, no, not right now. You just… stay here, okay? I’ll be back in a few.” she said, giving him a quick peck on the cheek before leaving him to stand there, dumbfounded.

Two minutes became five, five became ten, and ten was twenty before he knew it. Twenty minutes and not once had he seen his date, his girlfriend since they’d arrived. He was so nervous and anxious over that little fact, that when a loud but familiar shriek of happiness called out over the music behind him, he nearly jumped out of his skin.

“Dammit, Mabel! You nearly scared me to death!” he said, but he was glad for the company, laughing as he said it.

“You look plenty lively jumping three feet in the air, there, Dip-Dop! Why you just standing here holding a purse, though? I mean it kinda matches your vest but it’s not really your style, doesn’t even match the shoes,” she teased, ribbing him with an elbow. He laughed again, shaking his head.

“No, Rebecca told me to wait here while she got her socializing done before we start to dance. Dunno why it’s taking her so long.” Mabel frowned thoughtfully at his answer, then playfully poked his shoulder a few times.

“Hey, if she’s off doing her thing, I’m taking my promised dance time now!” she said as a lively song came through the DJ’s speaker setup, grabbing his wrist and tugging him out onto the dance-floor. He only hesitated for a bit before a tiny voice in his head said _what could it hurt?_ and before he knew it he was lost in the music, bouncing and wiggling alongside his sister as they bumped hips side-to-side, both laughing.

A crowd had grown around them while they boogied, both lost in their own little world while they danced, and when the song ended they both had struck a pose, and suddenly applause burst out around them. Dipper was just reveling in the great time he was having until he heard an angry voice off to the side.

“DIPPER PINES,” Rebecca yelled over the next song as it started up, and he turned to face her. Before he could even ask what was wrong, she snatched her purse away from his hand and stomped off into the crowd, leaving him utterly confused.

“What did I do?” he wondered aloud, and Mabel patted his shoulder.

“Hey, I’ll go see what’s up with her, don’t worry broseph,” she said, skipping off in his girlfriend’s wake. Feeling very vulnerable, alone on the dance floor all of the sudden, he managed to find an empty table to lean on.

———  
———

Mabel managed to find her arch nemesis ( _Is she my nemesis? Rival? I dunno but I hate her_ ) in a surprising hurry. Rebecca was grumbling to another pair of girls who were just half-nodding.

“…and then I find him dancing with his sister? It’s bad enough she’s always hanging around him between classes,” she was muttering, and Mabel paused to listen over the low growl of the current song. “I swear if he wasn’t so easy to get out of those raggedy clothes and looking acceptable I’d leave him just for this. Then the two weirdos would deserve each other.”

 _Oh, oh NO you did not just say that about my bro-bro!_ “Hey BECKY.” Mabel clamped a hand over her mouth after the hated moniker escaped, the raven haired bitch ( _Yeah she thought a curse word, what of it?!_ ) had wheeled around to glare at her.

“It’s REBECCA, you little freak! And what do YOU want?!” Mabel took a couple of deep breaths, cooling her own temper. She already hated this girl, why did she give a darn how Becky felt about her? This was about her Dipper.

“Why are you avoiding my brother? You drag him out here to the dance at an oh-so-specific time, just to get all weird and run away without him? Aren’t you at least gonna DANCE with him?” she asked, waving her arms around exasperatedly. The girl’s eye twitched a bit.

“Dance? Oh goodness no, I’m just here to listen to the music and socialize. Dancing is pretty much for those of you who can’t do that second part,” she sniped with a tone of smugness. “And you dragging my boyfriend into your own little activities is going to cost him, dearly.”

“You’re a goddamned bitch, Becky, and I hope the second he realizes it, you get bit in the ass!” _Whoadamn, Mabel, gettin’ mad? That’s a lot of bad words comin’ out of our mouth._ “Anybody with half a brain in their vapid, little, spoiled-bitch head would see he’s amazing without changing his behavior and image. So yanno what? I’m glad he danced with me, at least he got to have FUN.”

Becky’s face said it all, the irritated eye twitch, the way her lips twisted into a sneer. Man, she was ugly when she was angry. And, before she gave her the chance to say another word, Mabel stomped off away from her, only to hear the scorned brat trying to yell after her.

———  
———

Out of the corner of his eye he saw a glittery flash of purple coming his way. When he looked up at his sister, he noticed her fists were clenched tight, shoulders hunched as she stomped his way. “ _Becky Shitts_ , bitch-queen of the poopheads is on her way,” she growled, her tone furious.

 _Did… did Mabel just swear? Like actually use bad words out loud? What the hell happened?!_ This train of thought was followed closely by hearing his own name yelled from about ten feet away. Noticing Rebecca standing there, red in the face as she she pointed at him, then to her feet, wordlessly demanding 'You, here, now.’

“What’s going on, what did I do?” he asked when he got over to her. The question was innocent enough, he had no idea why she was so furious.

“What’s going on is that you’re out there, bouncing around in an undignified manner with that weirdo you live with,” she started ranting, and he felt anger bubble up inside of his gut when she referred to Mabel as a weirdo. “This isn’t just some silly dance, Dipper, this is THE PROM, you’re here supposed to be here with ME, and not out there acting like you aren’t!”

“Yeah, well, it’s kind of hard to dance, not to mention even spend the night with somebody who abandons you the second they arrive!” he snapped, hands clenched at his sides tightly. “And that 'weirdo’ as you so rudely call her is my sister, whom I love!”

“Oh please, we all know she’s the reason you don’t have any friends,” Rebecca snapped, jabbing a fingernail into his chest. “She follows you around school like a pathetic lost puppy. She’s the only person you ever really talk to, and if weren’t for me you’d still be a little friendless nerd.”

“In case you haven’t noticed, I happen to enjoy her company! She lets me be myself, and meanwhile all you’ve done is act like I need to be somebody else to be happy. And you know what? All you’ve done since we got together is insult my wardrobe and demand I change everything about myself. So you step back and listen to me, _Becky,_ ” he said before he realized the hated nickname had passed through clenched teeth, in the silence between songs.

The silence was punctuated with a sudden smacking sound as he felt Rebecca’s hand lash out across his face, her skin as red as her dress. “MY NAME IS _REBECCA_ ,” she screeched in the most undignified manner possible. It echoed through the suddenly silent gymnasium, everybody watching the sudden couple fight. “Nobody, NOBODY calls me 'Becky’!” she spat as he rubbed at his cheek.

“You know what? I just did. You don’t like my sister, fine. Stay away from both of us, we’re through. You can take the limo home alone,” he growled, turning around to march off. He slammed his way through the doors, listening to his now ex-girlfriend’s screams of rage drown out under the music that began to pulse once again.

Once he got outside, the heavy, overheated air of the dance evaporated and gave away to the cool night air. He sat down on a bench and hung his head in his hands, eyes burning as he tried to silence the buzz inside his skull. He heard the doors open a few times, only to hear hushed voices hurrying back inside after they saw him. _Yep, an outcast again, just like old times! But was that always so bad? At least I had Mabes for company, then._

He was still lost inside his own head when he felt the presence of somebody silently sitting next to him, and then fingernails gliding over his scalp gently, sending a shiver down his spine. “I’m so sorry,” he muttered, choking back a small sob.

“Hey, hey now,” his sister said, still rubbing at his head through his hair, “You didn’t do anything wrong.” He glanced up at her, her apologetic smile melting his efforts to stay calm in the face of what had just transpired.

“No, not for just now so much as not heeding your advice when this whole mess started,” he begrudgingly admitted. “Had I never started going out with Becky we’d have never fought and she wouldn’t have pissed you off tonight.”

“Nah, Dip-Dop, I’m still pretty certain that she would have found some way to infuriate me regardless. She’s a walking sack of bitch wrapped up in a pretty package.” Dipper caught himself laughing at that, the sound of mirth that escaped him vaporizing his stress. “Also, you broke up with her in the middle of PROM?! Wowwie, and I thought for certain that I’d be the one with the more dramatic Prom stories!” He laughed even harder, before he sighed sadly. She must have noticed how upset he still seemed, though. “Hey, what’s wrong?”

“It’s just, the reason I had to break up with her, Mabes. She started going off on me for having fun with you. She talked like you were an embarassment or something and that she thinks we spend too much time around each other, I couldn’t handle it,” he said, anger bubbling in his voice as he relived the experience. “I’ve just never heard anybody say anything so mean about YOU of all people, and I just-” he explained, but she quieted him with a finger pressed softly to his lips. She nodded back at the gym doors, where a familiar tune was drifting out to them.

“Hey, they’re playing our song,” she said as she stood and offered a hand, quickly adopting a phony British accent. “Shall we dance?” He just grinned and took her hand, tugging himself to his feet before he stepped up close, hands lacing behind her back. Her arms looped around his neck, hugging him in while she rested her head against his shoulder. When the lyrics started up, she just hummed along. He was the first one to start singing.

“What if I’m far from home?” he half-whispered, half-sang into her hair, and she sighed a little before responding.

“Oh, brother I will hear your call! What if I lose it all?” she sang back, her eyes buried in the crook of his neck, and for a moment he thought maybe she was crying.

“Oh sister I will help you ooouutt…” he sang back at her, the pair stepping back a bit to look at each other, each wearing a grin on their features as they sang together.

“Oh, if the sky comes falling down, for you, There’s nothing in this world I wouldn’t do.”

They just placed their foreheads together and lazily slow-danced through the upbeat instrumental, before Mabel managed to keep the sing-along going on the next verse.

“Heeeey, brother. There’s an endless road to re-dis-cover.” The way she sang it hit Dipper to his core, as though there was a springloaded coil of line between them, tugging them closer together. Her eyes bore into his, and he swallowed nervously. She smelled fantastic, fruity and faintly of vanilla, and her lips sparkled in the glow cast from the outside lights of the school, and good god if the way she bit her lower lip with those perfect, wonderfully white teeth didn’t cause his stomach to do a cirque de soleil act of its own accord.

“Heeeey, sister, do you still believe in love I wonder?” he managed to whisper, his voice husky and a little shaky. Her eyes gleamed into his own, lips pursing for a quick second before parting just a tiny bit to reflect the new layer of moisture. His stomach flung itself about his innards nervously, as though he was on the most rickety of roller coasters ever designed. _What is she doing to me?! This is your sister, she’s only doing this to help you feel better about the break u-_

Dipper’s brain misfired in that moment, the train of thought he was working on flying wildly from the tracks and crashing through the logic center of his brain. _Her lips are on mine, she’s kissing me,_ he managed to think in a panic. _My sister, Mabel, she’s kissing ME. MABEL is kissing ME._

Her lips had pressed to his hesitantly at first, then lingered for a brief moment before she kissed again, then pulled her head back to look up at him. Her eyes, she looked so uncertain, so scared, and he couldn’t think at all. All he knew in that moment was how soft her lips had been, how they had tasted so fruity and sweet and somehow so distinctly Mabel that his tongue worked nervously over his own lips to savor it. She was the first to break the stunned silence.

“I, I’m sorry, was that wrong of me? I know I might have freaked you out, it’s just I’ve been battling with a lot of stuff internally for awhile now, and us singin’ and dancin’ and junk pulled a lot of that to the surface and why can’t I stop rambling oh geeze I just thought in the moment it seemed like-” she said, the words pouring out nonstop until one of his hands pulled away from her back, cupping her cheek, and then tugged her back in for a second kiss, this time more feverish, his tongue taking the first exploratory prod at her lips. It was met with a stifled moan, and then by her lips parting and her own tongue giving a tentative lick to his own as if to say _hey, welcome to Mabel’s mouth! Hang out anytime_. When he broke the kiss all he could taste were cherries, bubblegum and vanilla, along with that certain sweetness he couldn’t really define, that seemed so wonderfully Mabel.

“Mabel, I love you,” he breathed in a whisper. He felt her tremble a bit, and he was suddenly unsure if he was doing the right thing but dammit, it was in the open now. “I can’t go through life without telling you that anymore.”

“You mean, like, brotherly love or-” she nervously sputtered, and he laughed, pressing his forehead to hers before he gently brushed their noses together.

“Mabel, when was the last time I ever gave you a 'brotherly-love’ kiss that involved my tongue? Or any kiss with my tongue? I mean, I know I’m a dud at this whole romance business but I figured that at least signified something. I’m sorry if what I’m saying, or what I did was too much but I couldn’t let myself lie like that anymore.” A shuddering breath welled up in his chest. “And I get it if this scares you, or you kind of hate me, but I just couldn’t risk losing my sister again, not if it was because I kept lying to you, or to myself.”

“Hey, bup-bup,” she said, tapping a finger to his lips. “Don’t worry, I’m not going anywhere, you aren’t losing me.” He frowned thoughtfully as he searched her face for any hint of dishonesty, to make sure she wasn’t just telling him what he wanted to hear. “I mean come on, bro-bro, who started the face-war right here?” She smiled up at him, a genuine, caring smile.

“So, uh, this is in the open between us now, huh?”

“Heh, yeah I guess. So, uh,” she asked, and he felt his heart pound, afraid of what she was going to say next. “How long?” He did nothing but blink, the question was kind of open ended and he didn’t know how to process it right away.

“Beg pardon?”

“How long have you been burying all these feels you have for me, Dipper?” she clarified, and he sighed with a smidgen of relief. Oh is THAT all.

“I guess about, three years or so? When puberty hit us both and you got all curvy and I turned into a lanky awkward child with a cracking voice-” she snorted a laugh and he powered through it, “-is when I first realized how pretty you were. Your smile, the day you got your braces off? That sealed it, though.”

She beamed up at him, with that exact smile ( _She’s doing this on purpose I fucking know it_ ), and then started to giggle. “What, what’s so funny about that?”

“Dipper, when we both hit the big ole p-word together you got tall and developed all these wiry muscles and stuff. And we’d always been really close so when my teenage hormones got all weird my mind latched onto you. Plus the way you treat me when you think a guy is going to hurt me or break my heart? Pffff, you’ve been the knight in shining armor for just as long!” He was baffled by this. His own sister, that he’d been secretly lusting after and in love with for years, had felt the same way all along?!

“I’m such a blind idiot,” he said with a laugh, and she giggled while she placed a gentle kiss on his chin.

“You can’t be blind, doofus, you just said you’ve been admiring my sexy hot Mabel bod,” she teased, giving herself a little wiggle for emphasis, making him laugh with her.

“I mean to have never seen the signs before,” he flatly explained before kissing her forehead. “But… what do we do about this? I mean, I’m pretty certain I’m never speaking to Becky again-”

“You better not!”

“- _ **because**_ we just broke up. What happens if we end up fighting and separating?” he said, nervously lacing his fingers into hers. “I almost lost you over a stupid girl, and that’s when we were just brother and sister. If we have to split for some reason, god forbid, I don’t know if I could handle losing you. Especially not now.”

She shook her head and placed a tender, lingering kiss on his lips. “Hey, you never will, I mean we’re brother and sister, we’ll always have each other’s backs,” she reaffirmed him, and right as she moved in for another smooch they heard the doors pop open, accompanied by hushed voices. They both stepped apart a bit, nervously glancing at the kids who had a hand rolled cigarette they were lighting and passing around. Yeah, no way those guys were going to go back inside anytime soon.

“So, uh, it occurs to me that we should be moving this… conversation of ours somewhere else?” he offered, his face reading like a deer trapped in headlights. She pulled the van keys from her cleavage ( _good god she’s been waiting to do that where I could see hasn’t she_ ), and gave them a small jingle.

“Shall we continue to 'talk’ in the van, my dear Sir Dippingsauce?” He grinned wide.

“I would be delighted, oh Lady Mabelton,” he said, offering a hand. She grabbed his fingers with a suggestive waggle of her eyebrows as they raced towards the parking lot and into the van once they had it unlocked.

Far away from the other students, nobody paid the fogging windows and loud music coming from the vehicle any mind. Nobody saw it about ten minutes later when the siblings inside quickly wiped the fogging glass down and drove off, singing together at the top of their lungs, no note of the song they sang to going unmolested as Avicii’s “Hey Brother” played on a loop while they drove home, hands clasped together as they went on to see where this exciting, frightening new road took them together.

_Together…_


End file.
